HMS Fearless was one of three Active-class scout cruisers built for the Royal Navy shortly before the First World War.

[1] The main armament of the Active class consisted of ten breech-loading (BL) 4-inch (102 mm) Mk VII guns.

[4] Fearless, the fifth ship of that name to serve in the Royal Navy,[6] was laid down at Pembroke Dockyard on 15 November 1911, launched on 12 June 1912 and completed in October 1913.

[4] On the morning of 4 August, Commodore Reginald Tyrwhitt, commander of the Harwich Force, led the 1st and 3rd Destroyer Flotillas on a patrol southeast to the vicinity of Borkum, one of the East Frisian Islands, off the Dutch coast.

[10] The Harwich Force turned west at 08:12 to disengage before any further German cruisers made an appearance, but Fearless spotted the torpedo boat SMS V187 three minutes later and opened fire without visible effect and V-187 was able to briefly disengage before being spotted by two light cruisers from the 1st LCS and several British destroyers that sank her.

[11] In the meantime, Tyrwhitt's flagship, Arethusa, was badly damaged by SMS Frauenlob and Fearless rendezvoused with her at 08:55 to cover her withdrawal.

Without Fearless in close support, things looked bad for the British destroyers as they had expended many of their torpedoes earlier in the battle, but the 1st LCS came into sight from the north at 11:50 and quickly began hitting the German cruiser.

Without knowing the target, the Admiralty realised that it was impossible to intercept the attack, but that it could position forces to get between the High Seas Fleet and its bases.

Six months later, two battlecruiser squadrons, escorted by Fearless and most of the 1st DF, covered the laying of minefields in the southern North Sea on 10 September.

When the British turned north after spotting the main body of the High Seas Fleet, the 1st DF fell in on the unengaged side of the 5th BS so that their funnel smoke would not obscure the battleships' view of their German opposite numbers.

As they got further north, the destroyers pushed forward to screen the battlecruisers while Fearless was too slow to stay with them and remained on the unengaged side of the 5th BS, and later of the Grand Fleet after the two forces rendezvoused.

That squadron's flagship, Marlborough, had been torpedoed earlier, but by the middle of the night she was forced to reduce speed and turn for home.

Vice-Admiral Cecil Burney, the squadron commander, summoned Fearless to the flagship to transfer him and his staff to the battleship Revenge.

The return voyage was rather eventful as the two ships engaged a Zeppelin without effect early on the morning of 1 June and Marlborough was near-missed by SM U-46 about 10:55.

Nine days later, Fearless sailed for Murmansk, Russia, and arrived there on the 19th to serve as the depot ship for several British G-class submarines based there.

[20] On the evening of 31 January 1918, the Light Cruiser Force sortied from Rosyth to participate in a training exercise with elements of the Grand Fleet.

In doing so, his ships crossed the path of the oncoming 12th SF and Fearless accidentally rammed and sank the submarine HMS K17.

The bulkheads in Fearless' bow had to be shored up to prevent further flooding, but she was not in any danger of sinking and returned to Rosyth at a very slow speed.